1. Technical Field
The present invention relates to a portable system capable of quickly diagnosing and monitoring pathogenic organs for men and animals on the site, and more particularly, to a condensing-type portable fluorescence detection system capable of detecting antigens using fluorescence at high speed and with high precision. Furthermore, the present invention relates to a condensing-type portable fluorescence detection system which overcomes the limit of a conventional fluorescence detection system having a maximum efficiency of 70% by condensing light directed to the opposite direction of a photodetector using only one dome reflector, and reflects even the fluorescence, which has been discharged from the conventional fluorescence detection system and corresponds to about 30%, using a spherical mirror, thereby theoretically obtaining an efficiency of 100%.
2. Related Art
Conventionally, Greencross MS, Inc. has developed a MITC (Magnetic ImmunoChromatographic Test) system to diagnose cardiovascular disorders from technology transferred from MagnaBioSciences, LLC in US. Furthermore, Boditech Med Inc. and NanoEnTek Inc. have developed a kit to diagnose cardiovascular disorders and the like using a laser bio diagnosis system.
An FICT (Fluorescence ImmunoChromatographic Test) system using laser has been developed by BioSite, Inc. in US and widely released with a product name called Triage. The FICT system having about 4 billion won in sales in Korea is forming a large market. In addition, many companies such as Inverness (US), Roche (Swiss), Abbott (US) are developing a large-scale diagnosis system using fluorescence.
However, in the case of a laser-induced fluorescence detection method which is widely used in the above-described conventional systems, a system for implementing the method has a complex structure. Therefore, the system had difficulties in diagnosing pathogenic organs on the site.
Accordingly, a portable fluorescence detection system to detect antigens at high speed and with high precision has been developed as part of the development for a portable system capable of quickly diagnosing and monitoring pathogenic organs for men and animals on the site.
First, referring to FIGS. 1 to 5, the basic structure and principle of a conventional fluorescence detection system will be described.
As a method of detecting fluorescence on a DNA chip or a protein chip using membrane, the laser-induced fluorescence detection method has been representatively used. The laser-induced fluorescence detection method excites a fluorescent material using laser as an excitation light source having a wavelength at which the fluorescent material is absorbed, measures the intensity of fluorescence emitted while the fluorescent material is moved to a ground state from the excided state, and measures the concentration of the fluorescent material in proportion to the intensity of each fluorescence. In this way, a fluorescent material may be added to a DNA or protein sample to perform quantitative analysis.
FIG. 1 illustrates a confocal laser scanning system 10 which is most frequently used among systems to detect fluorescence using the above-described laser-induced fluorescence detection method.
The confocal laser scanning system 10 receives fluorescence signals emitted from a sample through a photon multiplier tube using laser as a light source, and then converts the received fluorescence signals into a digital image. The confocal laser scanning system 10 excites only light at a wavelength suitable for a fluorescent material on the sample using a laser light source, and induces fluorescence emission. At this time, various types of filters such as a beam splitter may be selected, and a pin hole may be positioned in front of a photodetector so as to receive only a phase of which the focus is adjusted.
FIG. 2 schematically illustrates the entire structure of a conventional laser induced surface fluorescence detection system using an elliptical reflector mirror.
Referring to FIG. 2, the laser induced surface fluorescence detection system 20 generates fluorescence by projecting incident light on a sample arranged at a first focus of an elliptical reflector mirror 23, condenses the fluorescence and scattering light of the incident light on a second focus, and converts the fluorescence into parallel light to detect surface fluorescence. Specifically, light of laser 21 passes through an excitation filer 22, passes through a hole positioned at the middle position of the elliptical reflector mirror 23 disposed between the excitation filter 22 and a sample control unit 24, and is then condensed at a proper size on the surface of the sample fixed to the sample control unit 24.
The condensing point is positioned at the first focus of the elliptical reflector mirror 23. The fluorescence emitted from the first focus and the scattering light of the incident light are reflected by the elliptical reflector mirror 23 and condensed on a pin hole 25 serving as the second focus of the elliptical reflector mirror 23 and removing noise caused by dust or the like on the surface of the sample. Then, the light passing through the pin hole 25 is converted into parallel light by a collimator 26. While the parallel light passes through a fluorescence filter 28, the scattering light is filtered, and only pure fluorescence is incident on a photodetector 27. The fluorescence incident on the photodetector 27 is transmitted as a signal indicating fluorescence intensity to a computer 29 and then analyzed and processed. However, the confocal laser scanning system 10 and the laser-induced detection system 20 have a complex structure including the lens, the beam splitter, the laser and the like, require expensive equipments, and require a long time for detection. Therefore, there is a limitation in using the confocal laser scanning system 10 and the laser induced detection system 20 as an emergency and portable detection kit for various viruses.
As another conventional portable detection system, the present inventors have developed a portable fluorescence detection system as part of the development for a high-speed high-precision multi-antigen diagnosis machine and an early diagnosis system for infectious diseases of men and animals, based on a portable LED light source and a fluorescent substance. The portable fluorescence detection system has been disclosed in Korean Patent Laid-open Publication No. 10-2011-0032688 applied for on Apr. 8, 2011.
FIGS. 3 and 4 schematically illustrate the entire structure of the conventional portable fluorescence detection system proposed by the present inventors.
Referring to FIG. 3, the conventional portable fluorescence detection system 1 conveniently and quickly detects fluorescence of a sample 600 for a DNA chip or protein chip using membrane, and includes a light source 100, a rotating unit 300, a plurality of filter units 200, a curved reflector unit 400, and a photodetector 500.
The light source 100 includes an LED. The LED has a small size, a long lifetime, and various wavelengths, may be purchased at a low price, and has a wide choice of colors from a single color to a white color. Therefore, the LED may be suitably used as the light source of the portable fluorescence detection system 1. In this case, various elements having excellent fluorescence efficiency may be utilized according to LED wavelengths suitable for the respective elements.
Furthermore, a semiconductor laser which is usually used for fluorescence excitation has a limited wavelength range of choice and is very expensive or difficult to supply except for a specific wavelength range, even though it has a much smaller size than an existing gas laser. Therefore, the semiconductor laser is not suitable as the light source of the portable fluorescence detection system 1.
The rotating unit 300 has a plate shape. The filter units 200 are installed on one surface of the rotating unit 300 and selectively filter light emitted from the light source 100. The curved reflector unit 400 includes a mirror which is depressed inward to form a curved surface and installed on the opposite side of the surface of the rotating unit 300, where the filter units 200 are installed. The light source 100 is installed on a predetermined region of the outer surface of the curved surface reflector unit 400.
At this time, the curved reflector unit 400 may include any structures such as hemisphere, semi-ellipse, parabola, and quarter sphere, as long as they have a mirror depressed inward to form a curved surface. The photodetector 500 is installed on the opposite side of the surfaces of the filter units 200 which are contacted with the rotating unit 300, detects an optical signal generated when a fluorescent material of a sample 600 is excided by light generated from the light source 100, and converts the detected optical signal into an electrical signal.
The photodetector 500 may include a diode-type photodetector, a photoconductor-type photodetector, a camera, a CCD sensor, a CMOS sensor or the like, depending on the type of an optical signal to be detected. When a part of the components is removed, colors may be determined through user's naked eyes.
The filter units 200 serve to pass fluorescent light entering the photodetector 500 and block light of the light source 100, and may be installed at a predetermined distance from each other on one surface of the rotating unit 300 so as to transmit different wavelength ranges of fluorescence. At this time, the plurality of filter units 200 may be installed in such a manner that the centers of the filter units 200 are positioned on the same circumference.
Furthermore, the filter units 200 may pass different wavelengths depending on the positions thereof, and may be detachably installed on the rotating unit 300. At this time, the rotating unit 300 may include a rotating shaft 310 installed in the center thereof such that the filter units 200 may be replaced by the rotation of the rotating unit 300. Accordingly, since the filter units 200 can be easily replaced by the rotation of the rotating unit 300, the portable fluorescence detection system 1 may detect a plurality of fluorescences located at various wavelength ranges within a short time, without using a separate spectroscope. Accordingly, diagnosis may be performed quickly.
The curved reflector unit 400 may be installed in the opposite side of the surface of the rotating unit 300 on which the filter units 200 are mounted, such that the center thereof and the center of a filter unit 200 are positioned on the same vertical line. Accordingly, although a filter unit 200 is replaced by the rotation of the rotating unit 300, the center of the curved reflector unit 400 is positioned on the same vertical line as the center of the replaced filter unit 200. Therefore, a process of detecting fluorescence of the sample 600 is performed under the same condition for each of the filter units 200. At this time, the inner surface of the curved reflector unit 400 may be formed of any one of PDMS, epoxy resin, plastic, glass, and metal. When the curved reflector unit 400 is formed of plastic, the unit cost of production may be reduced, and the manufacturing speed may be improved. Accordingly, the reflector units 400 can be mass-produced.
The portable fluorescence detection system 1 may further include a motor installed on the rotating shaft 310 of the rotating unit 300 so as to rotate the rotating unit 300 at a constant speed about the rotating shaft 310.
Hereinafter, the operation of the portable fluorescence detection system 1 will be described as follows. First, fluorescence generated by the light source 100 is reflected by the inner curved surface of the curved reflector unit 400 and propagates toward the photodetector 500 through the filter unit 200. The curved reflecting mirror formed on the inner surface of the curved reflector unit 400 reflects the light of the light source 100 such that the reflected light excites a fluorescent material a plurality of times, thereby increasing the sensitivity of the photodetector 500.
Here, when a spherical mirror is not used as illustrated in FIG. 5A, only a part of light emitted from a fluorescent material is incident on the photodetector. However, when a parabolic mirror is used as illustrated in FIG. 5B, lights directed toward the mirror surface are vertically reflected. Therefore, although the photodetector is positioned at a remote position, at least 50% or more of lights may be detected. Furthermore, when a quarter spherical mirror is used as illustrated in FIG. 5C, lights are not reflected as vertically as the lights are reflected by the elliptical mirror. However, since the lights are relatively vertically reflected, detection efficiency is improved more than when a mirror is not used.
That is, the portable fluorescence detection system disclosed in Korean Patent Laid-open Publication No. 10-2011-0032688 may be conveniently carried because the portable fluorescence detection system does not use a lens and laser so as to be used as a detection kit for various fluorescent materials. Furthermore, since the portable fluorescence detection system may detect a plurality of fluorescences within a short time, diagnosis may be quickly performed. Furthermore, since the portable fluorescence detection system does not use expensive equipments such as lens, laser, and beam splitter, the cost may be reduced.
As described above, the principle that light is condensed by changing the optical path through the spherical or parabolic dome reflector has been proposed. However, the structure of a fluorescence detection system capable of condensing light emitted in every direction from a point light source into one region using spherical mirrors having different shapes and theoretically obtaining an efficiency of 100% and a method for manufacturing the same have never been proposed.